The exemplary embodiment relates to the linguistic processing arts. It finds particular application in conjunction with the creation of query expansion rules for knowledge base searching. However, it is to be appreciated that it is also amenable to other like applications.
Synonyms are useful in several contexts. For example, in information search systems, such as a device troubleshooting search engine, there is the need for the creation and maintenance of query expansion rules based on synonyms since the terminology used in the searchable content of a knowledge base is often different from the terminology used by the users of the search system. Troubleshooting systems with natural language query based user interaction usually provide efficient results only if the user has some expertise of the terminology used in the underlying knowledge base and is able to choose “good” words in the query. For example, technical terminology may be used, such as names of mechanical parts, operations on them, configuration settings, etc., which are often unfamiliar to the knowledge base users.
There is a great deal of literature in the field of information retrieval (IR) on techniques for what is generally referred to as query expansion. This term is used to describe techniques used in vector space IR models or Boolean search engines with an OR operator, when adding more words to a query results in more results being retrieved (and may also improve the ranking). These techniques involve supplementing the original query with additional words that are related to those originally entered by the user. The expansion may be performed interactively, where the user is asked to select relevant words or documents, or automatically, where the system expands the query “behind the scenes.”
In order to be useful, synonyms need to be defined precisely and selectively. In practice, a generic list of synonyms for natural languages may in some cases be missing domain-specific synonymies and in others introduce noise in the results when searching for a given type of information. In many instances it is impractical or difficult for an editor of the knowledge base to develop a collection of synonyms for each of the terms used in the knowledge base which can then be used to develop expansion rules for expanding a user's query. The editor may be unfamiliar with domain-specific terms. In addition, the editor generally needs to spend time evaluating whether the addition of new synonyms will have a negative impact on the search results by generating a large number of responses which would not be particularly relevant for a user. Accordingly, most knowledge bases have only a limited number of query expansion rules which allow substitution of one or more synonyms for a queried term.
The exemplary embodiment provides a method for developing query expansion rules which can be performed in at least a semi-automated manner, to improve searching of a structured knowledge base, such as a manual for troubleshooting of faults with electromechanical devices.